The Third Generation Project Partnership (3GPP) has developed the System Architecture Evolution (SAE) as the core network architecture of its future and Long Term Evolution (LTE) wireless mobile telecommunications standard. The main component of the SAE architecture is the Evolved Packet Core (EPC). The LTE/SAE network includes network entities supporting the user and control planes.
The Evolved NodeB (eNodeB) provides the LTE air interface and performs radio resource management for the evolved access system. The EPC will serve as the equivalent of General Packet Radio Service (GPRS) networks.
The Mobility Management Entity (MME), which is the key control-node for the access-network. It is involved in the bearer activation/deactivation process and is also responsible for choosing the Serving Gateway (SGW) when a User Entity (UE) initially attaches to the network and at handovers involving Core Network (CN) node relocation. It is also responsible for authenticating the user (by interacting with the HSS).
The Serving Gateway (SGW) routes and forwards user data packets, while also acting as the mobility anchor for the user plane during inter-eNodeB handovers and as the anchor for mobility between LTE and other 3GPP technologies. It also manages and stores UE contexts, e.g. parameters of the IP bearer service and network internal routing information.
The Public Data Network gateway (PDN-GW or PGW) provides connectivity from the UE to external data networks (PDNs) by being the point of exit and entry of traffic for the UE. A UE may have simultaneous connectivity with more than one PGW for accessing multiple PDNs. The PGW performs policy enforcement, packet filtering for each user, charging support, lawful Interception and packet screening. Another key role of the PGW is to act as the anchor for mobility between 3GPP and non-3GPP technologies.
3GPP has standardized the Evolved Packet Core (EPC) starting from Release 8. The EPC contains a sophisticated policy control framework together with a detailed bearer mechanism for providing a variable Quality of Service (QoS) treatment to selected traffic. The standard specifies three key parameters that represent QoS for a bearer:                1. QCI: this dictates the packet level treatment for the packets traveling on the bearer, e.g., high reliability, low delay, or just best effort.        2. MBR and GBR: these specify, respectively, the maximum and guaranteed bitrates for the bearer.        3. ARP: the Allocation and Retention Priority, which is a value that governs admission control decisions for the bearer.        
There is also an Aggregated Maximum Bitrate (AMBR) parameter, which is the maximum limit of the user's combined traffic (all bearers), whereas the parameters listed above are applied per-bearer.
Quoting from 3GPP Technical Specification 23.401:                “The ARP shall contain information about the priority level (scalar), the pre-emption capability (flag) and the pre-emption vulnerability (flag). The primary purpose of ARP is to decide whether a bearer establishment/modification request can be accepted or needs to be rejected due to resource limitations (typically available radio capacity for GBR bearers). The priority level information of the ARP is used for this decision to ensure that the request of the bearer with the higher priority level is preferred. In addition, the ARP can be used (e.g. by the eNodeB) to decide which bearer(s) to drop during exceptional resource limitations (e.g. at handover). The pre-emption capability information of the ARP defines whether a bearer with a lower ARP priority level should be dropped to free up the required resources. The pre-emption vulnerability information of the ARP defines whether a bearer is applicable for such dropping by a pre-emption capable bearer with a higher ARP priority value. Once successfully established, a bearer's ARP shall not have any impact on the bearer level packet forwarding treatment (e.g. scheduling and rate control). Such packet forwarding treatment should be solely determined by the other EPS bearer QoS parameters: QCI, GBR and MBR, and by the AMBR parameters.”        
FIG. 1 is a schematic representation showing, for the purpose of the present disclosure, elements of the EPC architecture. These interact on one side with the CN, operated by a Network Service Provider (NSP), and on the other side with various Access Network technologies, operated by Access network Providers (ANPs) providing access to a customer's UE 10. Various network nodes are depicted as well as the designated interfaces between nodes. For the purposes of the present discussion it will be assumed that the UE 10 accesses a 3GPP/PP2 (LTE) access network, including eNodeB 12 and MME 13. The EPC network is operated by the EPC operator who is responsible for operation of the various gateway nodes, including SGW 14 and PDN-GW 15. The NSP operates an IMS network, communicating to/from the EPC network via a Policy and Charging Rules Function (PCRF) 16 over the Gx interface.
The logic of applying QoS is as follows. (This is a simplified and conceptual description of the 3GPP EPC mechanisms. For more details see 3GPP Technical Specification 23.401 and related documents.)
An application Function (AF—not shown) requests QoS for a piece of traffic from the PCRF 16 over the Rx interface. The traffic is described by IP flow filters. The AF also specifies what application (video, voice, etc.) this flow will carry and its bandwidth.
The PCRF 16 looks up which user the requested traffic belongs to. Then it checks its policy database to determine what QoS should be provided to this application for this user. Based on this it determines the QCI and ARP values.
The PCRF 16 requests configuration of the QoS rules (IP flow filters, QCI, ARP and bandwidth values) in the EPC network using the Gx interface.
A new bearer is set up (or an existing bearer is modified) using the received parameters. Each network node checks if it has enough resources to fulfill the request (honoring the ARP value). It is especially important for the access network to do this check for air interface resources, so in this example this is done by the eNodeB 12 in the LTE network, whereas in a Wideband Code Division Multiple Access (WCDMA) air interface, for example, this would be done by the Radio Network Controller (RNC). If the resources are adequate the bearer is set up. Incoming data packets are carried by the bearer having the QoS specified by the QCI.
Note that, in accordance with the requirements of LTE, the EPC supports non-3GPP accesses, such as fixed, WiFi or WiMax. In that case the access network would not necessarily set up bearers, but a different terminology or mechanism is used.
Nevertheless the main principles are the same: the PCRF determines the QoS parameters and the network performs the admission control and packet scheduling.
A disadvantage of the current EPC operation becomes apparent if the EPC is shared between multiple NSPs. For example, an EPC operator may own or rent a transport network, and own and operate EPC nodes. It may also be an ANP that owns or rents wireless or wired access networks. It can therefore provide a complete IP access network service to NSPs, who own subscribers. Such an IP access network service would comprise:                Secure physical connectivity to subscriber devices from all (any) of the access networks they support up to the location of NSP entities.        Seamless Mobility between and within access networks.        QoS provisioning and policy enforcement at the request of NSPs.        Facilitating Authentication, Authorization and Accounting (AAA) interaction between the user and the NSP (i.e. relaying of AAA messages from a user to the NSP).        Any other value-added, in-path service, such as transcoding, caching, Legal Intercept, etc. that may be specified in an agreement with the NSPs.        
The NSPs in this arrangement do not have to concern themselves with managing the bearer resources, such as the bandwidth, or the flow of data between the devices (i.e. the bitpipe). Instead, they can focus on customer experience and services.
It is envisaged that the NSPs would make policy decisions themselves and so for this reason the PCRF 16 is located in the NSP network, as shown in FIG. 1. However, in order to provide a single point of contact for policy related requests, the EPC operator may decide that it is best not to allow the PCRF nodes of NSPs to connect directly to the GW nodes of the EPC, but instead to provide a proxy node that would receive Gx messages from the NSP, make local adjustments (such as QCI translation and ARP adjustments) and pass the messages on to the relevant GW nodes. This proxy node is shown as a p-PCRF node 18 in FIG. 1, although this is not a specified EPC entity and is not essential for the purposes of the invention to be discussed below, which is equally applicable in cases where the PCRFs connect directly to the GW nodes.
With the current Gx interface parameters, it is not possible to implement a scheme where, for example, the capacity of the bearers used by two NSPs is split. For example, a Service Level Agreement (SLA) between NSPs may specify that the capacity is split between the NSPs according to a predefined percentage, say 50%-50%. In the case of admission control, this would require the admission control decision to take into account how much bearer traffic is currently being used by each NSP. However, this information is not currently available in the network nodes making admission control decisions (such as the eNodeB or RNC, among others). The network nodes also have no information about which NSP originated any new incoming request for bearer resources.
A similar situation arises for packet scheduling of non-guaranteed bit-rate traffic. The network can apply fair scheduling between users, but if, for example at a cell, one NSP has many more users than another NSP, then the resources are currently provided to NSPs in proportion to the numbers of current users, and not 50%-50% as the SLA would require. Again this is due to the fact that the nodes of the network have no information as to which traffic belongs to which NSP.
The present invention has been conceived with the foregoing in mind.